It shows that urea contains polyglutamic acid. According to relevant public information, polyglutamic acid is an ecological fertilizer additive fermented by microorganisms. When added to urea, the fertilizer utilization rate can be increased by about 8%, the average yield of crops can be increased by 10-25%, and the yield of root crops can be increased by 30-60%. Urea is a neutral fertilizer, which is suitable for all kinds of soils and plants. Easy storage, convenient use and little damage to soil. It is the chemical nitrogen fertilizer with the largest dosage and the highest nitrogen content at present.